This invention relates to air motors, and in particular to pneumatic cylinders. The invention is more specifically directed to a pneumatic cylinder in which the cylinder housing and the piston are made of plastic synthetic resin.
Conventional pneumatic cylinders are invariably of metal, as is the piston. A separate sealing member which can be rubber, leather, or another material is carried on the cylinder to piston to make a sliding seal between the piston and the wall of the cylinder bore.
Pneumatic cylinders are used extensively in the manufacture of polyfilm products, for example, for operating blades and punches for perforating plastic film bags and the like. These cylinders typically operate at high speed for extended intervals. Pneumatic cylinders typically generate high levels of noise as well. With conventional pneumatic equipment it is difficult to meet the noise standard of the Occupational Safety and Health Administration (OSHA), which does not permit noise in the workplace to exceed a level of 82 dBA. Where there are large numbers of these cylinders operating at the same time, such as in the manufacture of plastic film products, it is virtually impossible to meet the standard without employing numerous acoustic baffles and sound absorption materials over the machinery.
Conventional cylinders are also rather time consuming to repair when repairs are necessary, but are too expensive simply to replace and discard.